Bringing the "functionally extinct" American chestnut back from the dead
Summary
The American chestnut, functionally extinct due to blight, is the focus of a multi-pronged restoration effort using traditional breeding, hybrids with Chinese chestnut, and biotechnological approaches. A large-scale study infected thousands of trees, tracked resistance for over a decade, and produced high-quality chestnut genomes to identify resistance factors, revealing many small-effect genetic sites and a few larger-effect alleles that influence growth and resistance. The researchers emphasize genomic-guided breeding and potential gene-editing avenues, while noting challenges such as growth-rate tradeoffs and the risk of inbreeding when reintroducing blight-resistant trees to the Appalachians.